silent warnings

Hi,

I'm getting a lot of such 

PHP Warning: filectime(): stat failed for images/products/2/522834a3a5eed.jpg in /home/travis/build/expcommerce/exp/vendor/gregwar/image-bundle/Gregwar/ImageBundle/Image.php on line 879

warnings while running behat tests. Can we silent this?

Best regards,
Michal